• Title/Summary/Keyword: Well-Resistance

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Wire-wrap Models for Subchannel Blockage Analysis

  • Ha K.S.;Jeong H.Y.;Chang W.P.;Kwon Y.M.;Lee Y.B.
    • Nuclear Engineering and Technology
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    • v.36 no.2
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    • pp.165-174
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    • 2004
  • The distributed resistance model has been recently implemented into the MATRA-LMR code in order to improve its prediction capability over the wire-wrap model for a flow blockage analysis in the LMR. The code capability has been investigated using experimental data observed in the FFM (Fuel Failure Mock-up)-2A and 5B for two typical flow conditions in a blocked channel. The predicted results by the MATRA-LMR with a distributed resistance model agreed well with the experimental data for wire-wrapped subchannels. However, it is suggested that the parameter n in the distributed resistance model needs to be calibrated accurately for a reasonable prediction of the temperature field under a low flow condition. Finally, the analyses of a blockage for the assembly of the KALIMER design are performed. Satisfactory results by the MATRA-LMR code were obtained through and rerified a comparison with results of the SABRE code.

Determination of Insulin Signaling Pathways in Hepatocytes

  • Kim, Sang-Kyum
    • Toxicological Research
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    • v.21 no.3
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    • pp.195-208
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    • 2005
  • Diabetes is a major cause of morbidity and mortality, and associated with a high risk of atherosclerosis, and liver, kidney, nerve and tissue damage. Defective insulin secretion in pancreas and/or insulin resistance in peripheral tissues is a central component of diabetes. It is well established that, regardless of the degree of muscle insulin resistance, glucose levels in diabetic and non-diabetic individuals are determined by the rate of hepatic glucose production. Moreover recently studies using liver-specific insulin receptor knockout mice show the paramount role of the liver in insulin resistance and diabetes. Insulin exerts a multifaceted and highly integrated series of actions via its intracellular signaling systems. The first major section of this review defines the major insulin-mediated signaling pathways including phosphatidylinositol 3-kinase and mitogen activated protein kinases. The second major section of the review presents a summary and evaluation of methods for determination of the role and function of signaling pathways, including methods for determination of kinase phosphorylation, the use of pharmacological inhibitors of kinase and dominant-negative kinase constructs, and the application of new RNA interference methods.

Improvement of the Corrosion Resistance of PVD Hard Coating/Substrate Systems - Recent Developments -

  • Jehn, Hermann A.;Kang, Sung-Goon
    • Journal of the Korean institute of surface engineering
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    • v.32 no.3
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    • pp.472-483
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    • 1999
  • Hard coatings playa continuously increasing role in the field of tribology as well as for decorative applications. In both areas they are often also exposed to corrosive media. While especially hard nitride coatings show a high corrosion resistance for themselves, hard $coating_strate systems may suffer from a severe corrosion attack due to the defects in the coating structure (pores, pinholes) resulting from the PVD-typical film morphology. While a huge number of investigations cover the tribological properties, only limited studies deal with the corrosion behavjour of coating substrate systems and attempts are made to improve their corrosion resistance. The present paper shortly describes the corrosion mechanisms and repots characteristic examples of the system behaviour. Special emphasis is laid on recent investigations to improve the corrosion resistance by alloying, interlayers or multilayered coating structures.es.

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Improvement of corrosion resistance and hardening the back ferrule surface by plasma treatment (Back ferrule 의 내식성과 체결시 기계적특성을 만족시키는 최적의 플라즈마 침질탄화공정조건의 확립)

  • Lee, In-Seop;Debnath, Sanket
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2012.05a
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    • pp.179-180
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    • 2012
  • Back ferrule is a circular ring shaped metallic object which is used for fastening, joining or reinforcement during the tube fitting as well as to prevent leakage. Therefore, during tube fitting the leading edge of the back ferrule should be sufficiently hard enough to prevent leakage. In our research, we concentrated the improvement of two major factors. Firstly, to improve the surface hardness of the back ferrule made by AISI 316 Stainless Steel. Secondly, the enhancement of corrosion resistance of back ferrule after plasma treatment. Initially, the corrosion resistance and hardness of the back ferrule (both commercial and without treated) was not good enough for tube fitting but after applying plasma treatment with suitable conditions on ferrule, we improved the corrosion resistance and hardness of the back ferrule dramatically.

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Analysis of Ground Resistance Reduction Effect by Common use of Ground Poles (접지극의 공용화를 통한 접지저항 저감효과 분석)

  • Hong Sung Taek;Lee Eun Chun;Shin Gang Wook
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.440-442
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    • 2004
  • The ground resistance of middle scale ground pole was measured by using the 'fall of potential method' suggested by IEEE However, the measured resistance value was lower than the minimum value required To solve this problem. ground pole was set to be used commonly. In this research. ground resistance was measured using the newly suggested method and the results were analyzed to see if they satisfied the domestic regulation The results of this research will be applied to the management works as well as the establishment of new plan.

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Regulation of skeletal muscle protein synthesis by amino acid and resistance exercise

  • Nakai, Naoya
    • Korean Journal of Exercise Nutrition
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    • v.15 no.4
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    • pp.153-161
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    • 2011
  • The maintenance of skeletal muscle mass is very important for the prevention of life style-related diseases and the improvement of quality of life. It is well-known that resistance exercise and nutrition (especially amino acids) are the most effective interventions for maintaining skeletal muscle mass. It has been reported that many molecules are involved in the regulation of protein synthesis in response to resistance exercise and nutrition. Understanding the molecular mechanisms regulating muscle protein synthesis is crucial for the development of appropriate interventions. The role of intracellular signaling pathways through the mammalian target of rapamycin (mTOR), a serine/threonine protein kinase in the regulation of muscle protein synthesis, has been extensively investigated for these years. Control of protein synthesis by mTOR is mediated through phosphorylation of downstream targets that modulate translation initiation and elongation step. In contrast, upstream mediators regulating mTOR and protein synthesis in response to resistance exercise and amino acid still needed to be determined. In this brief review, we discuss the current progress of intracellular mechanisms for exercise- and amino acid-induced activation of mTOR pathways and protein synthesis in skeletal muscle.

Ofloxacin Resistance Mechanism in PA150 and PA300-Clinical Isolates of Pseudomonas aeruginosa in Korea

  • Lee, Soon-Deuk;Lee, Yeon-Hee
    • Archives of Pharmacal Research
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    • v.21 no.6
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    • pp.671-676
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    • 1998
  • Five hundred and seventy clinical strains of Pseudomonas aeruginosa were isolated from August 1993 to August 1994 in Korea and screened for their resistance to ciprofloxacin, norfloxacin, and ofloxacin. Among these, two P. aeruginosa strains (PA150 and PA300) were selected based on their strong resistance (MICs > 50mcg/ml) to all three quinolones. The susceptible strain as well as two resistant strains had proton gradient-dependent efflux system. Efflux system in PA300 showed different specificities to ofloxacin and ciprofloxacin while PA150 had less permeability for ofloxacin. Ofloxacin had a less inhibitory action on DNA synthesis in permeabilized cells of PA150 and PA300 than 1771M. When quinolone resistance determining region (QRDR) in gyrA was sequenced, PA300 had one missense mutation, Asn 116Tyr, which was newly reported in this work. The results showed that PA150 became ofloxacin resistant by reduced ofloxacin accumulation due to the existence of efflux system and low permeability, while resistance of PA300 was due to the efflux system and a mutation in QRDR of gyrA -the target site of quinolone.

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Bearing Capacity and Control Method of Driven Piles (기성말뚝의 지지력 거동해석과 시공관리방안)

  • 박영호;김경석
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.249-258
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    • 1999
  • Dynamic load and static load tests are performed on steel pipe piles and concrete piles at five construction sites in highway to compare the difference of load bearing mechanisms. At each site, one steel pile is instrumented with electric strain gages and dynamic tests are performed on the pile during installation. Damages of strain gages due to the installation are checked and static test is performed upon the same pile after two or seven days as well. It shows that load transfer from side friction to base resistance behaves somewhat differently according to the results of load-settlement analysis obtained from PDA and static load test. Initial elastic stage of load settlement curves of two load tests is almost similar. But after the yielding point, dynamic resistance of pile behaves more stiffer than static resistance, thus, dynamic load test result might overestimate the real pile capacity compared with static result. Analysis of gage readings shows that unit skin friction increases exponentially with depth. The skin friction is mobilized at the 1∼2m above the pile tip and contributes to the considerable side resistance. Comparison of side and base resistances between the measured value and the calculated value by Meyerhof's bearing capacity equation using SPT N value shows that the calculated base resistance is higher than the measured. Therefore, contribution of side resistance to total capacity shouldn't be ignored or underestimated. Finally, based upon the overall test results, a construction control procedure is suggested.

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Effects of Static Contact Angle and Roughness on Rolling Resistance of Droplet (액적의 구름저항에 대한 정접촉각 및 거칠기의 영향)

  • Cho, Won Kyoung;Cho, Sang Uk;Kim, Doo-In;Kim, Dae-Up;Jeong, Myung Yung
    • Journal of the Microelectronics and Packaging Society
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    • v.23 no.1
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    • pp.23-28
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    • 2016
  • In this study, the effects of the contact angle (CA) and contact angle hyteresis (CAH) of planar and nano-patterned surfaces on rolling resistance of water droplet were studied. Based on the investigation on the CAH of water droplet on surfaces with various static wettability, it was found that the rolling resistance coefficient of water droplet is highly influenced by the surface pattern as well as CAH. The observed results suggest that the optimal surface patterns should be designed in order to minimize the rolling resistance of water droplet for the practical applications where superhydrophocitiy is required.

A Study on the Relationship between the Water Resistance and Air permeability of the Water Resistance Finished Fabrics (시판 방수가공직물의 방수성과 공기투과성과의 상관성에 관한 연구)

  • 김은화
    • Journal of the Korean Home Economics Association
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    • v.20 no.3
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    • pp.19-24
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    • 1982
  • This study was carried out to investigate the relationship between the water resistance and the air permeability. The results are as follows; 1. In case of the water proofing fabrics, We cannot find that there is any relationship between the water resistance and the air permeability according to the kinds of finishing, while in case of the water repellent finished fabries, we can find that there is a correlationship between them, especially the hydrostatic pressure and the air permeability are found to have negative correlation. 2. In case of the water proofing fabrics, the relationship between the water resistance and the air permeability is not affected by the thickness of the fabrics. On the other hand, in case of the water repellent finished fabrics, the relationship between them is affected by the thickness of the fabrics. Especially, the relationship between the hydrostatic pressure and the air permeability as well as the relationship between the water repellency and the air permeability is effect much by the thickness of the fabrics, too. 3. In case of the water proofing fabrics, the relationship between the water resistance and the air permeability is not affected by fabric count. On the otherhand, in case of the water repellent finished fabrics, the relationship between them is affected by the fabric count. Especially, the relationship between hydrostatic pressure and the air permeability, and the relationship between the water proof and the air permeability are affected much by fabric count.

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